300 AAC Blackout and "rimmed" 300 Blackout

[schuetzen]

I've been intrigued with the 300 Blackout.  With the virtual unlimited supply of .223 brass, performance that approaches 7.62x39mm, AR-15 compatibility and .300 Whisper barrels available for some other platforms, I decided to see how easy it is to make 300 Blackout cases from .223 Rem.


I recently ordered a set of Lee dies to give it a try.  Following some posts I read on the internet, I removed the decapping pin from the FL sizing die and found it was very easy to press them without even needing any lube on the cases.  After that, trimmed them to length and then resized them again with the decapping pin installed.


I also found it interesting that a .357 Magnum case can be resized to make something like a "rimmed" 300 Blackout (far right in photo).  The case length of the 357 Magnum is about 1/16 inch shorter than the 300 Blackout making for a slightly shorter neck.  I understand that the 357 Maximum cases are built for higher pressure and could be used to the proper length, but with the on-and-off-again supply of 357 Maxumum cases, I thought a 357 Magnum case would be a curiosity.  Surely someone has already made this wildcat.

[twoshooter]

I have some dummy rounds in my collection, but I am still waiting to see a rifle and a range report. Many here are considering it as the only viable alternative to stubbing a 32/20.

[stimpylu32]

I can see were it could be an advantage to have a rim cut in the chamber , kinda like the Handi's that have been done to shoot both 307 rimmed and 308 rimless .
 
Also in a worst case SHTF type thing , the 357 needs no trimming , just size and load .
 
stimpy